Problem: Let $a$ and $b$ be complex numbers: $\begin{align*} a &= 4 - 5i \\ b &= -2 + 4i \end{align*}$ What is $a+b$ ? $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$ $11$ $\llap{-}2$ $\llap{-}3$ $\llap{-}4$ $\llap{-}5$ $\llap{-}6$ $\llap{-}7$ $\llap{-}8$ $\llap{-}9$ $\llap{-}10$ $\llap{-}11$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$ $11$ $\llap{-}2$ $\llap{-}3$ $\llap{-}4$ $\llap{-}5$ $\llap{-}6$ $\llap{-}7$ $\llap{-}8$ $\llap{-}9$ $\llap{-}10$ $\llap{-}11$ $a$ $b$
Solution: Sum the real and imaginary components separately. $a + b = (4 - 2) + (-5 + 4)i$ $\hphantom{a + b} = 2 - 1i$